A. Field of the Invention
The device of the present invention relates generally to a new and improved high voltage cable termination and, more particularly, to a new and improved high voltage cable termination connector assembly for use with many sizes of high voltage power cables.
B. Description of the Prior Art
Many high voltage power cables have been and are being manufactured with either segmented or nonsegmented center conductors formed from aluminum wire strands rather than copper wire strands due to the availability of aluminum wire and its usually lower cost. The use of aluminum wire strands does, however, have its disadvantages. One major disadvantage is the rather rapid formation of aluminum oxide coatings on the outer surfaces of the aluminum wire strands and of associated aluminum connecting devices. Such coatings retard the flow of electrical current across the junction formed by the aluminum wire strands and a connecting device. In addition, aluminum wire strands experience relatively rapid metal fatigue when subjected to extreme hot and cold expansion and contraction cycles caused by changes in the ambient temperature and the operation temperature of the electrical system.
Many different types of connectors are used in the prior art to electrically connect the center conductor of a terminated high voltage power cable to an external electrical connector. U.S. Pat. No. 3,796,821 illustrates one type of a prior art high voltage cable termination connector that has been used for smaller power cable sizes. A single device illustrated in U.S. Pat. No. 3,796,821 is not adaptable for use with power cables of widely varying sizes and wire gauges. Thus, different cable termination connectors of the type illustrated in U.S. Pat. No. 3,796,821 must be available for use with substantially different sized power cables.
U.S. Pat. No. 4,046,958 illustrates another type of cable termination. In this type of cable termination connector assembly, a multi-barrel connector is utilized for use with different sizes of high voltage power cables. A plurality of apertures are formed in the connector for receiving the wire strands of a segmented or nonsegmented center conductor of a high voltage power cable. A pair of set screws associated with each of the apertures force the wire strands of the center conductor against the inner walls of the apertures to retain the wire strands.
When a power cable is terminated, the conductor is exposed by removing some lengths of both the insulation and the outer conductive cable sheath or shield. The outer conductive cable sheath is removed to terminate the sheath within the termination assembly at the lower end. The cable insulation layer is removed or stripped back to the extent necessary to insert the center conductor into the connector assembly. The length of the strip-back is inversely related to an internal, longitudinal dielectric strength of the terminator assembly and thus it is desirable to minimize the amount of strip-back. This increased longitudinal dielectric strength is particularly desirable for DC voltage applications. Also where internal capacitor control of the terminator electrical field is utilized to reduce the physical size of the termination reduction of cable insulation strip-back allows the capacitor units to be stacked closer to the connector end of the terminator, thus allowing further reduction in the size and cost of the terminator. While the cable termination connector assemblies of the prior art are generally suitable for their intended purpose, it would be desirable to provide a connector assembly that reduces the amount of cable insulation strip-back thereby increasing the dielectric strength of the terminator assembly or reducing the physical size of the terminator.
Due to the increased usage of segmented or nonsegmented center conductors formed from aluminum wire strands, it is extremely important that the conductor assemblies of the cable termination assembly provide more uniform radial distribution of current density about the longitudinal axis of the connector and achieve electrical and mechanical contact with a maximum percentage of the conductor strands.